Hello I'm trying to disable certain tabs based on a property in a custom Xamarin.Forms content page. I added a handler to the TabLayout's TabSelected event to keep on the current selected tab if the other tab can not be selected. However, the event keeps fire indefinitely. I made pretty sure that it's only getting registered once so I'm not sure why it does so
public class ExtendedTabbedPageRenderer : TabbedPageRenderer
{
public ExtendedTabbedPageRenderer(Context context) : base(context)
{
}
private TabLayout _tabLayout;
ViewPager _viewPager;
private IList<ContentTab> _customTabs;
private int _lastSelectedPosition;
protected override void OnElementChanged(ElementChangedEventArgs<TabbedPage> e)
{
base.OnElementChanged(e);
for (int i = 0; i < ChildCount; i++)
{
var view = GetChildAt(i);
if (view is TabLayout layout)
_tabLayout = layout;
else if (view is ViewPager pager)
_viewPager = pager;
}
_customTabs = e.NewElement.Children.Select(p => (ContentTab)p).ToList();
//_tabLayout.AddOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(_viewPager));
_tabLayout.TabSelected += TabLayoutOnTabSelected;
List<TabLayout.Tab> tt = new List<TabLayout.Tab>();
for (int i = 0; i < _tabLayout.TabCount; i++)
{
tt.Add(_tabLayout.GetTabAt(i));
}
}
private void TabLayoutOnTabSelected(object sender, TabLayout.TabSelectedEventArgs tabSelectedEventArgs)
{
var tab = tabSelectedEventArgs.Tab;
if(tab.Position.Equals(_lastSelectedPosition))
return;
var customTab = _customTabs[tab.Position];
if (customTab.EnableUserInteraction)
{
tab.Select();
_viewPager.SetCurrentItem(tab.Position, true);
_lastSelectedPosition = tab.Position;
return;
}
_viewPager.SetCurrentItem(_lastSelectedPosition, false);
var lastTab = _tabLayout.GetTabAt(_lastSelectedPosition);
lastTab.Select();
}
Okay as I inspected through the TabbedPageRenderer source code, I found out that it has a private implementation for TabLayout.IOnTabSelectedListener which causes it to always try to select the tab once the user interacted with the the solution was to call
_tabLayout.ClearOnTabSelectedListeners();
on the OnElementChanged